Method of casting ingots.



L. W. SOUTHGATE.

METHOD 0F CASTING INGOTS.

APPLIoATIoN FILED 00T. a, 1901.

964,576.' Patented Ju1y19,191o.

WMM*

senate.

METHOD 0F CASTING INGOTS.

Specication`of-Letters atent.

Patenten-Junio, icio.

` Application filed October -8, 1907. Serial No. 396,488.

To all whom 1li may concer/n:

` Bie it known that I, LOUIS W. SOUTHGATE,

acitizen of the United Statesfresidin'g at Worcester, in the county of Worcester and State of Massachusetts, have invented a new and useful Method of Casting lngots, of which the following is a specilication. ln casting ingots, particularly steel ingots, fromme/Bessemer converter, diliiculty is encountered` in getting a perf t cast. These ingots are cast on the end., As the metal necessarily cools and sets first at the sides of the mold, the contraction has .to take place at the center where the metal is fluid or partially fluid. This causes a funnel-shaped hole to be formed from the top down into thelcenter of the mold, sometimes extending twenty to thirty per cent. of the length of the cast. This is called piping. The walls of this pipe oxidize s the metal cools and no amount of rolling will weld and risk.

the pipe and eliminate the imperfection. This necessitates cutting olf enough of the upper end of the cast ingot to eliminate this flaw. If the flaw remalns in theI ingot below what-is cut oan imperfection remains and it may be very serious if the ingot is rolledinto rails. This piping occasions loss The objectief the present invention is to reduce and eliminate, so far as poss1ble, this piping. Todo this proceed as follows:v

After the mold is poured in the usual way, a cap or jacket is-dropped down on top of the mold so'as to cover up a considerable portion of the sides and top thereof. This cap is constructed, so far as is possible,4 to retain the heat in the upper part of the mold and to keep the 'metal in the upper partvof the mold molten for a long time so that as the 'cast solidilies,4 the heat ofthe molten metal will keep the space produced by contraction filled so that no separation can take place. It has been found that a vacuum will almost perfectly prevent dissipation of heat and to utilize this principle, the cap above referred to is made hollow and air ,exhausted therefrom. This hollow-walled cap, Vwhen'placed on the top of the mold after the ingot has. been poured, willhkeep. the top of the ingot in molten condition. If'

desired, the action of cooling from the bottom of the mold may be carried up toward the top thereof in a progressive manner,

drawing in which,

either by arranging the cap so that there will be a dissipation of heat throughthe Y same, which dissipation is gradually diminished toward the top, or by gradually raising the cap 0E of the mold.

The invention will now be described in detail, reference being had to the annexed Figure 1 is an end view showing the cap in posit1on on a mold. Fig. 2 is a similar view illustrating the progressive raising of the cap. Fig. 3 is a view vShowing the stripping of the mold fromthe ingot. Fig. 4 'is a sectional view on enlarged scale through-V- the top of the cap or jacket and ImOld, and Fig. 5 is a cross sectional view taken on `the line '.5-5 of Fig. Il..

Referring to the drawing and in detail, A designates therniiold. These molds are placed on cars usually in pairs for convenient manipulation. The only change that is made in the mold is that the ears (t-a by .which the mold is stripped from the ingot are placed at a lower point thereon.

B represents the cap or jacket. This is made in the form of a hollow-walled cap which can fit approximately tightly to the top of the mold and which has depending i walls which extend down to "cover and protect the sides of thel mold the desired deee. 'This is usually a little more than onehalf of the mold. The cap or/jacket is provided with an opening which can be tightly closed with a suitable plug b. The cap or jacket is usually made out of cast metal and after casting, the air exhausted therefrom and the opening into theinside of said cap is sealed. The cap or vjacket may be provided with a vent 7 for the escape of gas.A

or jacket is also provided'with ears The cap he sides of the walls of the jacket bute which extend down over the'upper end of the mold may be connectedby cross pieces C, as shown, the numberof which, horizontally speakinglwill diminish toward the top of the xmold, as shown in dotted lines in Fig. 1. The upper end of the cap or jacket is ...usually provided ,with a/ filling of `refractory material yto prevent/the heat of the ingot from melting the wall which goes over the top of the mold.

The invention 1s carried out asilfollows:

'After the mold is cast, `the same is run to position where a .cap or jacket can be jacket. After the cap or jacket is in place to form in the ingot.

on the mold, the ingot is allowed to cool. The heat of the ingot will be dissipated out through the lower part of the sides of the mold where the same is not protected by-the cap or jacket and the upper part of the ingot will be kept molten by said cap or jacket. This will allow the molten metal'to fill up any pipe or hole which may tend The cap or jacket will keep the metal molten for the time necessary for this purpose.V The progressively diminishing number of bars C will allow the cooling of the ingot to take place up in that part of the mold which is covered by the jacket progressively, so that the cooling will take place as much as is possible progressively up from the bottom of the mold and the top of the ingot will be kept molten as long as is possible. The same edect may be obtained by gradually raising the jacket o ofthe mold as shown in Fig. 2. The

mold is stripped from the ingot by the usual arms of the crane engaging the ears w-a andldrawing the mold o of the ingot while a ram or plunger 'engages the top of the ingot and keeps the samefrom lifting, as

shown in Fig. 3.

I The invention as previouslydescribed may be readily worked out, so as to be practiced in connection with the ordinary plants and various forms of cranes and devices may be applied for applying and removing the caps or jackets. The'caps or jackets are especially well adapted` for the purpose described, as owing to the construction of the jackety shown, the loss of-heat will be very small. Moreover, as the cap or jacket fits approximately tightly' to the mold, loss b convection will be practically eliminate Moreover, no strain will be put upon the walls ot the jacket as the same receives the heat from the mold byreason of any expansion or contraction of the heat insulator which is the vacuum. Many other forms of apparatus may be devised for Carr ing outA rom thel my invention without departing scope thereof as expressed 1n the claims.

Having thus fully describedmy invention, l

the Iingot cools and-the upper part of the ingot 1s keptmolten, and gradually removing the insulation upward.

2. The method of reducing or preventing the formation of a pipe in a metal casting, which consists in locating an external removable heat insulating instrumentality around the upper part of the sides and top of the moldto keep the metal molten at the top of the mold to allow the ingot to cool from the bottom.

3. The method of reducing or preventing the formation of a pipe in an ingot, which consists in placing around the upper part ot' the mold when the ingot is cooling from a molten state, a jacket which extends down to cover part of the sides of the mold, said jacket having a space from which air is exhausted, whereby the top of the mold will be surrounded by a vacuum. Y

4. The method of producing ingots, which consists in applying a jacket having a space from which air is exhausted, to the upper part of the mold while the metal is solidifymg.

5. The method of producing ingots, which consists in applying a jacket having a space from which air is exhausted, to the upper part of the mold while the metal is solidifying, whereby dissipation of heat from the upper part of the mold isV reduced and progressively allowing the dissi ation of heat through the protected part o the mold.

6. The method of. producing ingots, which consists in applying a jackethaving a space from which air is exhausted tofa part ot' the mold while the metal is solidifying. v In testimony whereof I have hereunto set my hand, in the presence of two subscribing 4 witnesses. v

v LOUIS W. SOUTHGrATEv Witnesses:

j C. FoRRnsT WIssoN,

MARY E. REGAN. 

